3)Frame structure of binary signals

Each binary signal frame is comprised of the following sequence and fields. However, some binary signals do not have the FIF field inserted.

F

 

F

 

A

 

C

FCF

FIF

FCS

F

 

 

 

 

 

 

 

 

 

 

 

 

Preample

 

 

 

 

 

 

 

 

F

:

Flag sequence

 

 

 

 

 

 

 

 

Indicates the start or end of a frame. Also establishes the frame synchronization.

A

:

Address field

 

 

 

 

 

 

 

 

 

 

Informs the address.

 

 

 

 

 

 

C

:

Control field

 

 

 

 

 

 

 

 

 

 

Informs if this frame is the last one in this procedure.

 

 

FCF: FAX control field

 

 

 

 

 

 

 

 

Informs the type of the binary signal.

 

 

 

 

FIF:

FAX information field

 

 

 

 

 

 

 

 

Informs FAX information such as the functions.

 

 

 

FCS: Frame check sequence

Checks if there was any error in the transmission from A to FIF.

-Format of F, A and C

 

 

 

 

 

Format

 

 

 

 

 

 

 

 

 

 

 

 

 

 

b1

b2

b3

b4

 

b5

b6

b7

b8

F

0

1

1

1

 

1

1

1

0

 

 

 

 

 

 

 

 

 

 

A

1

1

1

1

 

1

1

1

1

 

 

 

 

 

 

 

 

 

 

C

1

1

0

0

 

x

0

0

0

 

 

 

 

 

 

 

 

 

 

*When this frame is the last frame, X = 1.

3

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Toshiba GD-1220, GD-1221 service manual When this frame is the last frame, X =, Fcf Fif Fcs, Format